I have an Atmega2560 on a protoboard and i'm looking for the correct bootloader. The bootloader folder in my arduino directory only has the stk500boot_v2_mega2560.hex file located in the stk500v2 folder. Is this the correct one? Do the fuse bits below look correct?

The IDE v1.0.4 or v1.0.5, \hardware\arduino\bootloaders\stk500v2\stk500boot_v2_mega2560.hex should be the latest corrected bootloader file.

Also you can use the same bootfile for the meag2560 or mega2560V @ 8MHz and 57600 baud. Just create a new boards.txt entry for it. The mega2560 and mega2560V have the same support, only the max clock speed and voltage ratings are different.

Does this mean arduino bootloaders will work at any speed without recompiling?

Yes, if you adjust the upload.speed as well. If you take a bootloader that uploads at 115200bps when running at 16MHz, it should work fine uploading at 57600bps when running at 8MHz.Changing to clock frequencies that result in non-standard bitrates (say, running at 10MHz, yielding 72000bps) might be more of a challenge, depending on the pickyness of your app/os/driver/serial chip.

I am also using the stk500boot_v2_mega2560 on a 2560V running on 3.3V at 8MHz. I am programming this with an AVRISP mkii It was working beautifully until my code size grew past about 21kBytes. When my hex size is less than that critical size, it works perfectly. Going above that gives me verification errors, such as:

arxwjh

Yes that is the right bootloader, but dont use that one. It has a bug in (I wrote it).

The bug is any sketch with "!!!" will hang the bootloader

I have tried to attach the new bootloader hex file but it gives me a "Folder full" error

send me a pm with your email address and I will send you the updated file

Mark

I have the same problem, i made a bord using a mega2560, and i always met some errors caused by the stk500v2_mega2560 i guess, cause i checked the other parts of the bord. So, i want a stable version about the bootloader, thanks a lot.My email address: arbalest.micheal@gmail.combtw, my IDE version is 1.5.7

Mark's message is from several years ago. The "!!!" fix has been in the bootloader sourcecode that's distributed with the Arduino IDE (hardware/arduino/avr/bootloaders/stk500v2/stk500boot/*) I think the .hex file there is recent as well.

Unfortunately, I don't think that "they" have updated the version that is loaded into the actual MEGA boards.